Musculocutaneous nerve substituting for the distal part of radial nerve: A case report and its embryological basis

Aberrant Superficial Branch of the Radial Nerve-Radial Forearm Free Flap Considerations

The superficial branch of the radial nerve (SBRN) is encountered and must be preserved during the harvest of a radial forearm free flap (RFFF). An abnormal course of the SBRN was encountered during the harvest of an RFFF. The nerve had an abnormal course with two branches—in the proximal forearm, one branch was anterior and the second branch was posterior to the brachioradialis muscle and in the distal forearm, both of these nerves merged together. A review of the literature was performed, with no such documented aberrant course of the SBRN being described previously. Knowledge of the SBRN anatomy and its variations is important to note during the RFFF harvest.

Reinnervation of Extrinsic Finger Flexors and Brachioradialis 22 and 36 Months Following Traumatic Pan-Brachial Plexopathy: A Case Report

A 25-year-old man sustained a right-sided brachial plexus injury from a high-velocity motocross accident. Physical examination and electromyography were consistent with a pan-brachial plexopathy with no evidence of axonal continuity. The patient underwent a spinal accessory to suprascapular nerve transfer and an intercostal to musculocutaneous nerve transfer with interpositional sural nerve grafts. He recovered MRC 4/5 elbow flexion and MRC 2/5 shoulder abduction and external rotation. Twenty-two months post-injury the patient displayed a flicker of flexion of his flexor pollicis longus and flexor digitorum profundus to his index finger - he went on to recover a functional pinch. Thirty-six months post-injury the patient displayed a flicker of contraction in brachioradialis with motor unit potentials on electromyography. This case demonstrates that some patients may have capacity for functional recovery after prolonged denervation and highlights the potential impact of anatomical anomalies in the assessment and treatment of peripheral nerve injuries.

Surgical Implications of Innervation Pattern of the Triceps Muscle: A Cadaveric Study

The innervation pattern of triceps is complex and not fully comprehended. Anomalous innervations of triceps have been described by various authors. We have attempted to delineate the nerve supply of the triceps and documented the anomalous innervations of its different heads. The brachial plexus and its major branches (in the region of the axilla and arm) and triceps were dissected in 36 embalmed cadaver upper limbs. Long head received one branch from radial nerve in 31 (86%) specimens. Four (11%) specimens received two branches including one that had dual innervation from the radial and axillary nerves, and one (3%) specimen had exclusive innervation from a branch of the axillary nerve. Medial head received two branches arising from the radial nerve in 34 (94%) specimens. One (3%) specimen received three branches from the radial nerve whereas one (3%) had dual supply from the radial and ulnar nerves. Lateral head received multiple branches exclusively from the radial nerve, ranging from 2 to 5, in all (100%) specimens. Knowledge of the variations in innervation of the triceps would not only help the surgeon to avoid inadvertent injury to any of the nerve branches but also offers new options for nerve and free functional muscle transfers.

Unusual bilateral sensory innervation of the dorsum of hand by lateral antebrachial cutaneous nerve: a case report

A 68-year-old male cadaver showed bilateral variation in the sensory innervation of the dorsum of hand. On the dorsum of right hand, first digit and lateral half of second digit were supplied by lateral antebrachial cutaneous nerve (LABCN); medial side of second digit and lateral side of third digit were supplied by superficial branch of radial nerve (SBRN) and medial side of third digit, the fourth and fifth digits were supplied by dorsal cutaneous branch of ulnar nerve (DBUN). On the dorsum of the left hand, lateral side of first digit was supplied by LABCN, medial side of first digit, the second and third digits as well as the lateral side of fourth digit were supplied by SBRN; medial side of fourth digit and fifth digit were supplied by DBUN. These variations would be helpful in understanding peripheral neuropathy, in interpretation of conduction velocity studies and in reconstructive surgery of hand.

Ultrasonographic and Surgical Findings of Acute Radial Neuropathy Following Blunt Trauma

Ultrasonographic study is useful for decision making of treatment for focal neuropathy with unusual electrodiagnostic findings. We present a patient with severe acute radial neuropathy with sensory sparing around the distal arm secondary to twisting of the radial nerve following blunt trauma. A 24-year-old man with a 2-week history of left wrist drop and severe pain around the left elbow presented after hitting the left distal arm on the doorknob. The left wrist and finger extensions were grade 0, but elbow extension could not be tested because of severe pain during this action. The left superficial radial sensory territory was intact. Electrodiagnostic findings suggested severe left radial neuropathy around the distal arm with sensory sparing. Ultrasonographic study demonstrated 2 stenotic lesions around the distal arm and absence of the left superficial radial sensory nerve. Surgical exploration revealed 2 stenotic lesions with twisting of the nerve, concordant with ultrasonographic study. End-to-end anastomosis was performed in the proximal lesion. Sixteen months later, wrist and finger extension was grade 3, and reinnervation signs in the radial-innervated muscles except extensor indicis muscle were observed. The complementary relationship between electrophysiologic and ultrasonographic examinations is very important for precise lesion location and decision making for treatment of peripheral nerve injury.

Superficial radial nerve-lateral antebrachial cutaneous nerve anatomic variation

INTRODUCTION

This study focuses on an anatomic variation in which the lateral antebrachial cutaneous nerve (LACN) innervates the radial border of the dorsum of the hand and thumb in addition to, or replacing, the superficial radial nerve (RSN). Here, we propose a technique of nerve conduction that identifies this variation.

METHODS

We studied nerve conduction in 200 upper limbs of two series of 50 volunteers. We sought evidence of the aforementioned variation on the dorsum of the hand and in the thumb.

RESULTS

We found eight occurrences of this variation on the dorsum of the hand and 11 variants on the thumb within the two respective series of 100 upper limbs studied.

DISCUSSION

The RSN-LACN anatomic variation can be studied using nerve conduction. The knowledge of this variation is particularly important for the evaluation of proximal radial nerve injury.